If the files are sorted (they are in your example):
comm -23 file1 file2
-23 suppresses the lines that are in both files, or only in file 2. If the files are not sorted, pipe them through sort first…
See the man page here
If the files are sorted (they are in your example):
comm -23 file1 file2
-23 suppresses the lines that are in both files, or only in file 2. If the files are not sorted, pipe them through sort first…
See the man page here